Why do some call it a truck but others say pickup ?

Worked in the offshore oil industry for many years. Everyone called those a "Rig" or "The Rig" or infrequently "Oil Rig" never a Semi Submersible Platform.

 

Heard a coworker call his suburu “my rig” today and i burst out laughing and said i didnt know a suburu outback qualified as a “rig” nowadays
Yes i used air quotes

 

Went off-roading in my rig today too. Got my rig a little muddy. Will have to detail it.

 

https://www.youtube.com/watch?v=UgdEJnsdOOU

 

OK, lets get some real answers here;
Pickup truck, it has a pick up bed, you can "pick up stuff", and bring it home. The pick up truck bed, and that's what a pick up truck is.
A flat bed is not a pickup truck, a cube van is not a pick truck, an SUV is not a truck, it's a people hauler, the new station wagon.

 

Every week I make a trip to the dump with family's garbage, recyclables and compost. Calling mine a dump truck.

 

Technically, it's a "truck" and "pick up" is an adjective. You could simply say truck but since there are so many styles of truck adding the adjective more clearly communicates what exactly it is. Using only "pick up" could relate to many things... food, women, etc, so the context of the sentence needs to be considered to understand what is being said. Same as using only "truck". Usually the context of the sentence will suggest the type of truck. FWIW, I usually say truck, or my truck and no one has ever misconstrued this and thought I was talking about an 18 wheeler or some such.

 

The way I was always told is a truck is a big vehicle, think like towing(Semis). Mid-size are pickups, although I never had them clarify if a diesel was a truck or pickup lol

 

The sexpot from post #19 finds your answer excessively pedantic.